All the things you say about becoming reclusive, battling with your own mind and the lack of concentration are all certainly symptoms of depression. I used to be in fierce battle with my own mind for a long time when I was also reclusive. To a degree, you could say I am still reclusive. The depression zaps all our energy, the confidence and self-esteem. The last thing we want to do is meeting and dealing with other people
I can understand the reluctance to move forward for help. I think we all chose the time when we were feeling ready to approach a GP. The first time is always the worst. We are opening ourselves up and baring our souls, so it is only natural we fear what happens next.... a fear of the unknown, really.
One day, you will feel ready. However, what I will add is that your GP will be interested in your depression. It's not a big thing to him/her. All you need to say is "I'm depressed" and he/she will talk you through the rest. In many ways, the quicker you get treatment, the quicker you start to recover
I use medication, as do many others on the Forum. It doesn't change your personality. If you find the right antidepressant for you, it can improve the quality of your life. Whatever you do, do not buy antidepressants via the net. They need doctor supervision. PLUS, they are known to be fake.
Sorry, got a bit carried away there. I hope you find the Forum helpful